Colors for Gum

Lawrence Shapiro (leshapiro@worldnet.att.net)
Wed, 11 Dec 1996 11:52:43 +0000

To all Gummists,
I have been doing some multiple color gum prints (not 3 color prints
just images where one tone is one color and another tone is a second
color). I have noted that some pigments deposit a much stronger layer
than others despite the dilution in the gum (or gloy) and dichromate
being held constant. For example phthalo blue and pyrol red deposit
very intense layers while greens, burnt umbers and siennas cover much
less. Rowney's Jet black gouache gives a dark black but I'm not sure
if its the pigment or the fact that it is a gouache. Some catalogues
of water color pigments note that a particular pigment is transparent,
semitransparent or opaque but I've not found this to be a useful guide
in trying to pick pigments. The best test I've found is actually
mixing up the pigment with the binder and the dichromate and making
an exposure.

What favor pigments, brands or types of paint are out there?

Larry Shapiro